Supplementary pages CT600I: supplementary charge in respect of ring fence trades
How to complete supplementary pages CT600I and what information you need to include.
When to complete
Complete these supplementary pages if for any period beginning (or deemed to have begun) on or after 17 April 2002 the company carried on a production ring fence trade under Part 8 of the Corporation Tax Act 2010.
Company information
I1 Company name
Enter the company name.
I2 Tax reference
Enter the company’s 10-digit Unique Taxpayer Reference.
Period covered by this supplementary page (cannot exceed 12 months)
I3
Enter the start date using the format DD MM YYYY.
I4
Enter the end date of the accounting period using the format DD MM YYYY.
Calculation of supplementary charge
I5 to I15 Supplementary charge in respect of ring fence profits
The Corporation Tax Act 2010 defines a ring fence trade in:
This covers oil extraction activities and any activities consisting of the acquisition, enjoyment or exploitation of oil rights in the UK or a designated area. In practice, this means all such onshore and offshore activities to the outer edge of the UK Continental Shelf.
The supplementary charge is applied to all adjusted ring fence profits arising on or after 17 April 2002. You must enter the figure of ring fence profit or loss of the accounting period after any group relief surrendered to the company and set against ring fence profits of the period (but before losses brought forward or carried back from other periods).
I20, I25 and I30 Disallowing financing costs
To arrive at the adjusted ring fence profits, the financing costs within the ring fence profits or losses are left out of the account. Financing costs are the costs of debt finance and include:
- costs giving rise to debits for debtor relationships of the company (read part 5 of the Corporation Tax Act 2009)
- exchange gains or losses in relation to debt finance
- credits or debits from derivative contracts in relation to debt finance (read part 7 of the Corporation Tax Act 2009)
- financing costs implicit in a payment under a finance lease
- any other costs arising from financing transactions
The financing costs you need to enter are those for this accounting period. If, exceptionally, net financing costs are negative and need to be subtracted from ring fence profits, the adjustment should be entered in box I50.
I35 Adjusted ring fence profits
Adjust the profits or losses shown in box I5 for the disallowed financing costs totalled at box I30, adding back the figure in I30 to profits or reducing losses. If the result is a loss enter 0 in box I35.
I40 Decommissioning adjustment
This box only applies when the rate of supplementary charge is higher than 20%.
For expenditure incurred in connection with decommissioning carried out on or after 21 March 2012, section 330A of the Corporation Tax Act 2010 restricts tax relief available for decommissioning expenditure for supplementary charge purposes.
It does this by increasing the profits liable to the supplementary charge where decommissioning expenditure is taken into account in reducing or eliminating those profits. The decommissioning expenditure may be so taken into account by being expenditure of the current accounting period or by being included in losses brought forward, carried back or surrendered to the company. Enter the amount of the increase in box I40.
I45 Revised ring fence profits
Enter the revised ring fence profits after applying the decommissioning adjustment.
I50 Losses brought forward or from later accounting period
If the company has set losses brought forward from earlier periods or back from later periods against its profits of the period for Corporation Tax, those losses need to be reduced for calculating the supplementary charge to remove financing costs.
Losses brought forward will be the accumulated losses as calculated using the assumption that finance costs are left out of account in calculating the amount of the profits or loss of any ring fence trade of the company for an accounting period (read section 330(3) of the Corporation Tax Act 2010).
Losses of a later period under section 37 of the Corporation Tax Act 2010 will be as calculated using the assumption in section 330(3). The total entered in this box cannot exceed the amount entered in box I45.
Where decommissioning expenditure is included in losses brought forward or carried back, increase the adjusted ring fence profits of the accounting period by the appropriate fraction of the decommissioning expenditure taken into account in reducing profits of the accounting period. Enter the amount of the increase in box I40.
Decommissioning adjustment
I55 Decommissioning reduction
Where decommissioning expenditure reduces the amount of Petroleum Revenue Tax (PRT) chargeable, section 330B of the Corporation Tax Act 2010 provides a reduction from profits liable to the supplementary charge where the profits resulting from the reduction in PRT would be subject to supplementary charge at a rate of more than 20%.
Enter the amount of this reduction in this box. Do not enter an amount greater than that needed to reduce I65 to nil.
I60 Field Allowance
Enter the amount of Field Allowance. Include any claim for onshore allowance in respect of capital expenditure incurred on and after 5 December 2013. Do not enter an amount greater than that needed to reduce I65 to nil.
Include any claim for high pressure high temperature cluster area allowance, onshore oil and gas allowance or investment allowance in this box. For more information read:
- high pressure high temperature cluster area allowance
- onshore oil and gas allowance
- Investment Allowance
I65 Net profit subject to ring fence charge
Enter the figure in box I45 minus the figures in boxes I50 to 165.
I70 Tax at supplementary charge rate
For accounting periods beginning on or after:
- 24 March 2011 the supplementary charge is 32%
- 1 January 2015 the supplementary charge is 20%
- 1 January 2016 the supplementary charge is 10%
In calculating the amount of supplementary charge for an accounting period beginning before 1 January 2015 and ending on or after that date, treat the period falling before 1 January 2015 and the period falling on or after that date as separate accounting periods.
In calculating the amount of supplementary charge for an accounting period beginning before 1 January 2016 and ending on or after that date, treat the period falling before 1 January 2015 and the period falling on or after that date as separate accounting periods.
Apportion the profits between those separate accounting periods in proportion to the number of days in those periods. However, if time apportionment gives a result that is unjust or unreasonable, the company can elect for a basis that is just and reasonable. If these circumstances apply, contact your HMRC tax office for advice.
Enter the figure from box I70 into box 505 of your CT600 form.
Losses (where appropriate)
I75 Ring fence trade loss of the period
This should be the ring fence trade loss of the company in the period as calculated using the assumption in section 330(3) of the Corporation Tax Act 2010.
Net ring fence trade
I80 and I85 Net ring fence tax
For accounting periods ending on or after 1 July 2005 liability to Corporation Tax and supplementary charge in respect of ring fence profits of a large company is payable in a maximum of 3 instalments. Tax on other profits remains payable in a maximum of 4 instalments. There are transitional arrangements for accounting periods beginning before 1 January 2016 and ending on or after that date.
Enter, in the relevant box, the figure you’ve calculated for Ring Fence Corporation Tax and the supplementary charge under section 330(of the Corporation Tax Act 2010 (previously section 501A(3) of the Income and Corporation Taxes Act 1988) after any further deduction in terms of tax.
This further deduction can only refer to deductions shown on the form CT600 after box 510 on that form. For instance, you may wish to reduce the figure of either the Ring Fence Corporation Tax or the supplementary charge by the Income Tax deducted from gross income included in other profits.
Enter the figures in boxes I80 and I85 into boxes 585 and 590 of your CT600 form.
Transferred tax history
On the sale of an oil and gas licence approved on or after 1 November 2018, the buyer may jointly elect with the seller of that licence to have part of the seller company’s tax history transferred to them in accordance with schedule 15 of the Finance Act 2019.
You need to complete this section if the company made a joint election to transfer tax history. Where the company has acquired transferable tax history (TTH), it’s required to submit details of the tracked profits of the transferred asset alongside its annual corporation tax return. Boxes I90 to I160 provide space for companies to provide that additional information, although these boxes do not form part of the company’s tax return.
I90 and I95 An election to transfer tax history has been made in the period covered by this return
Enter X in box I190 if the company made one or more elections on acquiring assets during the period of this return.
Enter X in Box I195 if the company made one or more elections on disposal of assets during the period of this return.
I100 and I105 An election to transfer tax history has been made in a previous accounting period
Enter X in box I190 if the company made one or more elections on acquiring assets during a previous accounting period.
Enter X box I195 if the company made one or more elections on disposal of assets during a previous accounting period.
Asset information and tracking
Complete boxes I110 to I160 for each asset acquired. You should complete and enclose an additional sheet where multiple assets have been acquired.
I110 Description of asset
Enter the name of the acquired field for which a transferable tax history election has been made.
I115 Asset reference
Enter the asset reference provided by HMRC when the particulars of the election and associated transferable tax history were agreed. It should be used in all future correspondence and Corporation Tax returns to uniquely identify the asset and associated transferable tax history in addition to the name or description provided.
I120 Put an X in box I120 if OGA has approved the cessation of production
Enter X if the Oil and Gas Authority (OGA) has approved the cessation of production in relation to this asset.
I125 Put an X in box I125 if STO certification of tracking is qualified
Enter X if the senior tracking officer (STO) certification is qualified or caveated. Part 9 of schedule 15 of the Finance Act 2019 requires the company to appoint a STO to oversee the ongoing tracking of profits and losses relating to this asset. The STO must provide certification for each accounting period that the profits have been appropriately tracked.
Tracking of transferred tax history
I130 Put an X in box I130 if a detailed schedule of the accounting periods and rates applying is included in the tax computations
Enter X if a detailed schedule is provided. A detailed schedule of the accounting periods and rates only need to be provided where the transferable tax history has been activated and used or sold on.
I135 Transferred tax history — Ring Fence Corporation Tax
A Amount brought forward or acquired
Enter the amounts of profits and tax included in the original election for this asset less any adjustments made in previous accounting periods.
B Amount transferred
If the asset or part of the asset has been disposed of, enter the amounts of profits and tax included in the original election which have been transferred on in this accounting period.
C Amount used this period
If a claim is being made for losses in this accounting period to be relieved against the transferable tax history for this asset, enter the amounts of transferable tax history profits being covered and the resulting tax being reclaimed.
D Amount carried forward
Enter the amounts of profits and tax included in the original election for this asset less any adjustments made in this and previous accounting periods. The profits and tax amounts should equal A minus the sum of B and C.
I140 Transferred tax history — supplementary charge
A Amount brought forward or acquired
Enter the amounts of profits and tax included in the original election for this asset less any adjustments made in previous accounting periods.
B Amount transferred
If the asset or part of the asset has been disposed of, enter the amounts of profits and tax included in the original election which have been transferred on in this accounting period.
C Amount used this period
If a claim is being made for losses in this accounting period to be relieved against the transferable tax history for this asset, enter the amounts of transferable tax history adjusted ring fence profits that will cease to be available to the company for future claims to be set against. This will not necessarily be the same as the amount of transferable tax history used for Ring Fence Corporation Tax purposes.
D Amount carried forward
Enter the amount of adjusted ring fence profits and supplementary charge tax that is still available to carry forward. The amounts should equal A minus the sum of B and C.
I145 Tracked profits or losses
A Amount brought forward
Enter the amount of net tracked profits or losses attributable to this asset in previous accounting periods since the asset was first acquired in a transaction where transferable tax history was transferred.
B Profits or losses for this period
Enter the amount of net profits or losses attributable to this asset in this accounting period.
C Other adjustments
Enter the amount of any adjustments required to the profits or losses brought forward, either as a reduction or an increase. For example, if all or part of the asset has been transferred on, the tracked profits may need to be reduced in proportion to the transfer.
D Amount carried forward
Enter the total amount of net tracked profits or losses attributable to this asset since it was acquired, including those for this accounting period.
I150 Decommissioning expenditure
When the total amount of decommissioning expenditure relating to this asset is equal to or greater than the net profits relating to this asset, the transferable tax history acquired with the asset becomes activated. From that point onwards, the transferable tax history is available for the relief of subsequent losses.
A Balance brought forward
Enter the amount of decommissioning expenditure incurred relating to this asset in previous accounting periods since the asset was first acquired in a transaction where transferable tax history was utilised.
B Expenditure for this period
Enter the amount of decommissioning expenditure attributable to this asset in this accounting period.
C Other adjustments
Enter the amount of any adjustments required to the decommissioning expenditure brought forward, either as a reduction or an increase. For example, if all or part of the asset has been transferred on, the attributable decommissioning expenditure may need to be reduced in proportion to the transfer.
D Amount carried forward
Enter the total amount of net decommissioning expenditure attributable to this asset since it was acquired, including those for this accounting period.
I155 Activated TTH — ring fence
A Previously activated
Enter the amount of transferable tax history ring fence profits and associated tax activated in previous accounting periods since the asset was acquired. The profit to include is the amount by which decommissioning expenditure in relation to this asset had exceeded the cumulative net profits in relation to this same asset at the end of the previous accounting period. The tax to include should be in the same proportion as the amount of profit to the total.
B Activated this period
Enter the additional amount of transferable tax history ring fence profits and associated tax activated in this accounting period. The profit to include is the amount by which decommissioning expenditure in this accounting period in relation to this asset has exceeded the net profits in relation to this asset in this accounting period. The tax to include should be in the same proportion as the amount of profit to the total.
C Total activated
Enter the totals of profit and tax entered in boxes I155 A and B, after making any further adjustments needed, for example if amounts are deactivated in accordance with Part 6 of schedule 15 of the Finance Act 2019.
D Total used
Enter the total amount of transferable tax history ring fence profits and tax against which claims for losses have been made in this or previous accounting periods.
I160 Activated TTH — supplementary charge
A Previously activated
Enter the amount of transferable tax history adjusted ring fence profits and associated supplementary charge tax activated in previous accounting periods since the asset was acquired.
B Activated this period
Enter the additional amount of transferable tax history adjusted ring fence profits and associated supplementary charge tax activated in this accounting period.
C Total activated
Enter the totals of profit and tax entered in boxes I155 A and B after making any further adjustments needed, for example if amounts are deactivated in accordance with Part 6 of schedule 15 of the Finance Act 2019.
D Total used
Enter the total amount of transferable tax history adjusted ring fence profits and supplementary charge tax which is no longer available to the company to set further losses against, as a result of claims for losses which have been made in this or previous accounting periods.
More information
Read the Oil Taxation Manual for more information.
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Last updated 2 January 2024 + show all updates
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